Gun charger



Dec. 3, 1957 T. F. FITZGIBBON ,971

GUN CHARGER 7 Filed May 4. 1953 3 Sheets-Sheet 1 th :0 a a N b w E 31 5 5 Q Q v a m E g u.

FIG. I

IN V EN TOR.

THOMAS F. FITZG!BBON I ATTORKJEY Dec, 3, 1957 r. F. FITZGIBIBON 9 GUN CHARGER Filed May 4, 1953 3 Sheets-Sheet 2 F|G.T

VALVE IN VEN TOR.

THOMAS F. F l TZ GI BBON- ATTORNEY Dec. 3, 1957 T. F. FITZGIBBON GUN CHARGER 3 Sheets-Sheet 3 Filed May 4, 1953 v /7 7 4/ r///6/ .N 5 mm mm 0m m. 0-

INVENTORY THOMAS-F. FITZGIBBON BY ATTORNEY tic GUN CHARGER Thomas F. Fitzgibbon, Los Angeles, Calif., assignor to North American Aviation, Inc.

Application May 4, 1953, Serial No. 352,734

Claims. (Cl. 89-.1)

This invention pertains to agun charger and more particularly to a device pneumatically operating the c'harg ing mechanism of an automatic machine gun.

As well known in the art, an automatic rapidly .fired gun, such as a machine gun, requires a gun charging device for operating the charging mechanism thereof. A charger of this type should be not only rugged and reliable in operation but for aircraft use should be fast acting, light weight, and operable for an unlimited number of times.

Therefore, it is an object of this invention to provide a quick acting pneumatic gun charger.

Another object of this invention is to provide a gun charger having positive means for exhausting vair therefrom.

A further object of this invention is to provide a gun charger having shock absorbing provisions for precluding damage thereto from the machine gun.

Still another object of this invention is to provide a gun charger which is operable an unlimited number of times.

Yet another object of this invention is to provide a gun charger which is light in weight and characterized by its rugged construction.

A further object of this invention is to provide a gun charger having automatically moved valve means for introducingand removing operating fluid from the gun charger.

A still further object of this invention is to provide a gun charger having a positive means for shutting ofi -the supply of operating fluid.

These and other objects will become apparent from the following detailed description taken in connection withthe accompanying drawings in which Fig. l is a plan view of the charger of this invention associated with an automatic gun,

Fig. 2 is 'a schematic view of the elements for operating the charger,.

Fig. 3 is a sectional view of the mechanism of the charger,

Fig. 4 is a sectional view taken along line 44 of "Fig. 3,

Fig. 5 is a sectional view of the charger with the piston and rod assembly in an extended position,

Fig. 6 is 'a sectional view taken along line 66 of Fig. 3,

Fig. '7 is a fragmentary schematic view of the solenoid valve in the bleed position,

Fig. '8 is a diagram of the wiring arrangement for controlling operation of the charger, and

Fig. 9 is a fragmentary sectional view of a modification of the invention wherein a shock absorbing device is employed.

"Referring to the drawing, as seen in Fig. 1, gun charger 1 of this invention is adapted to be attached in a suitable mannerto a machine gun 2. Such an automatically operating gun will include a slide 3 which operates the charging mechanism of the gun in a manner well known in the When moved to the left "from the'position illustrated the charging mechanism of the gun will be operated. Movement of member 3 to the right will be effected by the recoil of the gun. This gun charger is operable to move slide member .3 to the left for charging .the gun. This is accomplished by means of a reciprocal rod 4 which projects from :end 5 of the gun charger. Thus as illustrated in the drawing if rod 4 is extended to the leftso as to withdraw it further from charger 1 it will serve to move slide 3 likewise to the left. The operation of the gun will cause slide 3 to subsequently return to the right which will move rod 4 back to the retracted .position illustrated in Fig. 1.

Charger 1 of this invention is of the pneumatic type being operated preferably by compressedrair which reaches the charger through line 6 from a suitable air @compressor 7, illustrated schematically in Fig. 2. For installation on a .jetpropelled aircraft, compressor 7 may comprise the compressor of the jet engine, which is a ready source of a large quantity of pressurized air only a small amount of which will be required for operating the .charger of this invention. A shut-ofi valve .8 .may be included in inlet line 6 between the compressor and the .gun charger-so that the inlet supply of air may be closed off at appropriate times. Valve 8 .in the preferred embodiment-is a solenoid operated valve for reasons more .fully explained hereinafter.

Referring now to Fig. 3 the components of the ,gun

charger may be seen in the retracted position. The charger includes .a suitable housing 9 which as illustrated is made in several pieces for allowing-assembly and disassembly of the device. This housing isgenerally cylindrical in shape and a piston assembly .10 .is reciprocative therein. This piston is attached to rod 4 and i for the purpose of moving the rod. The piston is hollow to provide a centrally disposed recessed ,portion 11. Piston head portion1'2 is at the extremity of the pistonand an additional piston head portion 13 is within the recess.

' Piston head portion 12 is suitably sealed against the walls projecting lug 16. The cylinder head is sealed with respect to the housing wall by means of O-ring .17. The rod and piston assembly is received within sleeve bearings 18 and 19 so that the assembly is freely reciprocal within housing 9. The latter bearing is slotted longitudinally at 20 as shown in Fig. 4 to permit .air flow within the housing.

Disposed within the housing along the axis thereof is a 'valve member 21. This member serves to .direct the air from inlet line 6 to the interior of the housing for operating rod 4 through forces exerted-on the piston. Inlet line 6 connects with inlet passage 23 which leads to passage 24 and to annular port .25 surrounding the valve member. Valve 21 is provided with ahollow central bore 26 to which access is providedby a plurality of inlet ports 27 and outlet ports 28. As shown in Fig. 3 with the charger in its retracted position the valve is open so that inlet ports 27 communicate with inlet port.25of the'housing, while outlet ports 28 of the valve are closed oif. The valve passes through head 15 and is sealed with respect thereto by means of O-ring 29. The interior bore 26 of the valve member opens into the interior portion of'the housing beyond the cylinder head through open end 30 of the valve and also through a plurality of openings 31. The valve is suitably sealed within the housing by means of O-rings 32, 33, and 34 so that when to the left as shown in the drawing, actuating slide 3 of the gun in its charging operation. The piston and rod assembly is thereby extended to the position illustrated in Fig. 5. As this movement occurs inwardly extending annular shoulder portion 35 of the piston assembly engages radially outwardly extending end flange 36 of the valve unit. This engagement occurs only when the piston and rod have neared the end oftheir stroke in charging the gun which is accomplished, of course, by appropriate proportioning of the parts. When the piston so engages the valve it carries the valve with it to the left as it continues its movement. When the piston has reached the extremity of its movement piston head portion 12 will be in engagement with shoulder 37 of the housing.

The left portion of the housing is provided with a plurality of apertures 38 extending therethrough. These apertures enable the air which will be in the housing to the left of the piston assembly to be exhausted as the piston moves to the left. Thus there will be no cushioning action or force tending to'prevent the piston and rod assembly from moving to its extended position.

By being picked up by the piston near the end of its stroke and moved with the piston until the latter reaches a position of engagement with shoulder 37, the valve will be moved through a short stroke during the timethe piston is moved through a much longer stroke. This movement of the valve causes inlet valve ports 27 to move to a position remote from annular inlet port 25, thus closing off the air inlet to the housing. At the same time valve outlet ports 28 will be moved to a posi tion wherethey communicate with annular outlet-port 40 of the housing. Port 40 in turn connects with outlet passageway 41 which may communicate with the surrounding atmosphere. When the valve has been so repositioned it is obvious that the compressed air within the cylinder which had been admitted for pushing the piston to the left may now escape through the open end of the valve and through passageways 31 to interior bore 26 of the valve from which, through outlet ports 28,

outlet port 40 and outlet passageway 41, the air is exhausted to the atmosphere. Thus the interior of the housing is rapidly depressurized as the piston and rod reach the end of their stroke in a charging operation.

In order to axially balance the forces on the valve resulting from the compressed air within the housing a passageway 43 interconnects bore 26 and the right end of the valve. The projected areas of the right and left ends of the valve are so proportioned that when pressurized air is within the housing the forces exerted thereby on the two ends of the valve are the same so that the air will not tend to move the valve in either direction.

When the piston and rod 4 have so reached the end of their stroke and the air Within the cylinder portion of the housing has been ported to the atmosphere as described above, the slide 3 of the gun will be moved to the right by the action of the gun itself, thereby returning the rod and piston assembly to the right as it moves. This movement proceeds freely until the piston has been almost returned to the retracted position of Fig. 3. However, valve 21 has been moved to the left through its relatively short stroke as described above so that as the rod and piston near the end of their stroke to the right, central piston head portion 13 will engage flange portion '36 of the valve assembly. This will move the valve back to the right, returning it to the position of Fig. 3 thereby closing E outlet ports 28 and opening inlet ports 27. The valve action is thus made automatic as the charger operates.

In order that the valve will function properly and will always assume the required positions for controlling the inlet and outlet ports a detent assembly 45 is provided for positioning the valve at either end of its stroke. This detent assembly may include a ball-shaped end portion 46 which is adapted to engage either of grooves 47 .and 48 of the valve assembly. Ball member 46 is loaded by a spring 49 which urges it into engagement with the valve member. When the ball portion 46 is in engagement with groove 47 of the valve, the valve will be in the inlet position of Fig. 3, and when ball portion engages groove 48 the valve is in the exhaust position of Fig. 5. This detent arrangement will positively stop the valve at the desired position each time at the end of its stroke, yet by being spring-loaded will permit movement of the valve when it is engaged by the portions of the pistons for effecting the stroke of the valve member.

Rod 4 is also provided with a suitable stop means for precluding its inadvertent movement to the left when the gun is in operation and the charger is not in operation as when valve 8 is closed off. For this purpose the left end portion of the rod is provided with an annular groove 51 which is adapted to receive a plurality of balls 52. A ring 53, which includes a projection 54 in engagement with fixed shoulder 55 of the housing, engages the balls from one side. From the other side the balls are engaged by ring 56 which is urged against the balls by means of a spring 57. It is obvious therefore that when the rod is in the retracted position as shown in Fig. 3 spring 57, by urging ring 56 against balls 52 and the latter against ring 53, will urge the balls into engagement with rod 4 at the location of groove 51. This will serve to retain the rod in its stationary position. However, when subsequently air is admitted into the housing for actuating the charger the balls may be displaced from the groove by overcoming the force of spring 5'7, thus enabling movement of the rod through its stroke. When returned to the retracted position the balls will again engage the groove to position the rod.

As an additional feature of this invention there maybe provided within the right-hand portion of the housing a microswitch 60 the operation of which may best be seen in Fig. 6. This microswitch is of the type well-known in the art including an operating plunger 61 for closing the contacts of the switch. This switch is normally open and plunger 61 is biased outwardly. This switch is in turn wired to solenoid valve 8 for operation of the valve. For operation of switch 60 an arm 62 is carried within the housing and pivoted at 63. This arm engages extension 64 of the valve unit and is biased against this portion of the valve by means of spring 65. When the valve is in its open position but the piston and rod assembly is in the retracted position shown in Fig. 3, extension 64 of the valve will engage arm 62 holding it in a position as shown in Fig. 6 remote from switch plunger 61. However, when the valve is subsequently moved through its stroke and assumes the position of Fig. 5, projection 64 will be removed from engagement with arm 62 allowing spring 65 to force this arm into engagement with plunger 61 of the microswitch causing the contacts of the switch to close. When the valve is subsequently repositioned to its open position extension 64 will again force arm 62 away from plunger 61 so that the microswitch will be opened. End 66 of extension 64 is tapered so that it can readily move arm 62 away from the switch as the valve is returned.

The actuation of the gun charger of this invention can best be seen by reference to the wiring diagram of Fig. 7 and the schematic showings of Figs. 2 and 8. Valve 8 is a solenoid actuated valve arranged such that when the solenoid is energized the valve assumes the position of Fig. 2. When in this position inlet line 6 is open between the compressor and the gun charger so that compressed air is admitted into inlet passageway 23 of the gun charger housing. When the solenoid is de-energized the valve is arranged to assume the position of Fig. 7 wherein inlet line 6 is closed off between the compressor and the gun charger and the gun charger is ported through line 6 and the valve to the atmosphere. Solenoid valve 8 is connected to a relay 67 as shown in Fig. 8. This relay includes normally closed contacts 68. A switch 69 is included in the line beyond the relay and for aircraft use rod 4 .against the slide of the gunafor charging the .gun. When the gun charger piston .androd assembly move in iihe charging operation valve .21 will .be picked up .by the piston near the end of .its stroke, as described above. when this occurs extension 64 of the valve will be re- :moved from arm :62 so that the arm can :engage the iplung- "er of microswitch 6.0:causing .the switch to close. When this switch closes the circuit to relay 67 is closed which will cause the relay to open contacts 68. As a result the solenoid .is deenergized and the solenoid valve :8 is switched to a position of Fig. 7 wherein the tairinlet is .closed mi and the interior of the "valve is .ported to the atmosphere through line .6. The circuit to "the solenoid Will be held open by'the relay until'switch 69 is :manually opened and again .closed. This means that there will be no leakage .of inlet air into the interior of .the housing after the piston 'rod :assemhlyhas reached the end of its stroke. It also means that when the valve is returned to the open position the air within passageways 23 and '24 .and within line 6 will not be compressed by this movement of the valve because there will be an open passageway from the interior of the housing to the atmosphere through valve 8. Solenoid valve 8 is elfective for this purpose but can not perform the same function as valve 21 because it is inherently slower inaction.

.Because of the automatic closing of switch .60 when valve 21 moves to the left, the charger will make only one complete stroke each time switch 69 is closed. 'This prevents the unit from making repeated undesired charging strokes but permits additional operation of the charger by further operation of control switch 69.

An important modification of the invention 'is illustrated in Fig. 9. For this embodiment the end of rod 4 is provided with an additional plunger member 72 which is loaded and biased outwardly by means of a spring 73 which bears against plug 74 screwed into the hollow interior of rod 4 and held therein by pin 75. This additional plunger member has been found necessary in some installations to provide a shock absorbing action. It may occur that slide 3 of the gun will overtravel during operation of the gun while the charger is in its stationary position. It is of course important for the end of rod 4 to be close to slide 3 of the gun to therefore provide instant action and avoid impact contact with the slide of the gun when the charger is placed into operation. Therefore, if slide 3 does happen to overtravel it will violently strike the end of rod 4 and can cause damage to the mechanism of the gun charger. When spring-loaded plunger 72 is provided to project beyond the end of rod 4 this will act as a shock absorber and be the first portion of the rod to be engaged by slide 3 as it reciprocates with the gun. Forces exerted by the slide in engaging plunger 72 will be absorbed by the spring and will be reduced in violence thereby protecting the mechanism of the gun charger.

The foregoing detailed description is to be clearly understood as given as example only, the spirit and scope of this invention being limited only by the appended claims.

I claim:

1. A charger for an automatic gun having a reciprocative slide member associated therewith, said charger comprising a cylinder; a cylinder head in said cylinder, said cylinder having on one side of said cylinder head inlet port means and outlet port means whereby said inlet port means is adapted to admit pressurized fluid into said cylinder; a valve in said cylinder, said valve extending through said cylinder head in sealed relationship therewith, and reciprocative through a relatively :short :stroke', "said valve including an open passageway extending therethrough in communication ".Wllih the sinterior :of said cylinder and havingv inlet and .outlet means "for communication with said cylinder .port means, wherebyaatrone end of said :valvexstrokesaid Einletiportiis interconnected with said interior :of said cylinder, and :at tthe= other -=.end 50f isaid .istroke said :outlet port means *is interconnectedwithxsaid interior zofzsaid cylinder, ta rpiston in -said interior of:said cylinder,.said piston being1reiprolcative itherein through l-a relatively long stroke and including .a :projecting vro'd portion extending beyond said cylinder for engagement with said :side member :of .said 1 gun, :said :piston .being :movable in one direction :in :response :to fluid pressurein'said:cylinderwherebysaidn'od portion :moves said slide member for charging said :"gun, .said :piston including a projecting portion extending therefrom, said projecting 'portion being brought into engagement with :said valve when said :piston has approached the end :of :its .stroke :in said direction thereby moving sa'id'valve in the same direction through its stroke to a closed :position, said :piston being vmovable :in the opposite direction :by said gun slide member thereby :ex-

:hausting rsaid cylinder, said piston being adapted to engage said valve when said piston haslapproachcd the end of its stroke in :said opposite direction to thereby move :said valve .inzsaid direction through :its stroke to an open position.

2. Atcharger for anautomatic :gun having a reciprocative member associated therewith, said charger com- ;prising a cylinder, said cylinder having inlet and outlet port means; a cylinder head in said cylinder; a valve '-in said cylinder extending through said cylinder head and reciprocative through a relatively short stroke for controlling said inlet and outlet port means whereby pressurized fluid may be admitted to and exhausted from said cylinder through said valve means; piston means in said cylinder and reciprocative through a relatively long stroke, said piston means including a rod extending beyond said cylinder and adapted to engage said gun reciprocative member, said piston means being movable inone direction in response to pressurized fluid admitted by saidvalve means for thereby moving said gun reciprocative member, said piston having a recessed portion adapted to receive an end of said valve, said recessed portion including means adapted to engage said valve when said piston is moved in said one direction whereby said valve is moved through its stroke for closing said inlet port means and opening said outlet port means, said piston being adapted to move in the opposite direction in response to movement of said gun reciprocative member, and to engage said valve when near the end of its stroke in said opposite direction for thereby moving said valve in said opposite direction through its stroke for closing said outlet port means and opening said inlet port means.

3. A gun charger for an automatic gun having a reciprocative member, said charger comprising a cylinder, said cylinder having an inlet port and an outlet port; a source of pressurized fluid connected with said inlet port; a valve in said cylinder for controlling said ports; piston means in said cylinder, said piston means including a portion thereof adapted to engage said reciprocative member, said piston means being movable through a stroke in one direction in response to said pressurized fluid and including means for moving said valve to a closed position when said piston means is near the end of said stroke, said piston means being movable through a return stroke by said reciprocative member and including means for moving said valve to an open position when said piston means is near the end of said return stroke; a second valve means interposed between said source of pressurized fluid and said inlet port; and control means in said cylinder interconnected with said second valve means for operation thereof, said control means being associated with said first-mentioned valve means and automatically operable upon movement thereof whereby said control means closes said second valve means when said first-mentioned valve is moved to a closed position.

4. A gun charger for an automatic gun having a reciprocative member, said gun charger comprising a cylinder, said cylinder having an inlet port and an outlet port; a source of pressurized fluid; inlet line means interconnecting said source of pressurized fluid and said inlet port; a valve reciprocative in said cylinder between an open position wherein said inlet port is open and said outlet port is closed and a closed position wherein said outlet port is open and said inlet port is close-d; piston means .reciprocative in said cylinder and including a portion extending beyond said cylinder for engagement with said reciprocative member of said gun whereby when said valve is in an open position said pressurized fluid forces said piston through a stroke in one direction in response thereto, said piston means including a portion constructed to engage said valve when said piston is at a position remote from the beginning of its stroke for moving said valve to a closed position, said piston means being movable through a stroke in the opposite direction by said reciprocative member, said piston means further including a portion constructed to engage said valve when said piston is at a position remote from the beginning of its stroke in said opposite position for thereby moving said valve to an open position; a second valve in said inlet line between said source of pressurized air and said inlet port; power operated means for opening and closing said second valve; remote control means for efiecting operation of said power operated means to open said second valve thereby to admit pressurized fluid into said cylinder ior efi-ecting said reciprocative movement of said piston means; and a second control means for said second valve disposed in said cylinder and associated with said first-mentioned valve, said second control means being responsive to movement of said first-mentioned valve to said closed position for overcoming said remote control means and effecting movement of said second valve to a closed position.

5. A charger for an automatic gun having a reciprocative member, said charger comprising .a cylinder, said cylinder being provided with inlet port means and outlet port means providing access to the interior thereof; a gun actuating member reciprocative within aid cylinder, said member including a piston portion and a rod portion,

said rod portion having a hollow outer end portion; 'a plunger in said end portion normally extending therebeyond, said end portion and said plunger projecting through said cylinder and adapted toabuttingly engage said reciprocative memberof said gun; resilient means in said end portion for biasing said plunger member ou twardly for cooperating with said plunger to absorb impact loads exerted by said reciprocative member; a valve slidably received in said cylinder, said valve being reciprocative through a stroke and cooperating with said port means whereby at one end of said valve stroke said inlet port means is open and at the other end of said valve stroke said outlet port means is open; and a source of pressurized fluid connected with said inlet port means whereby when said inlet port means is open said fluid enters said cylinder to contact said piston portion to thereby force said gun actuating member toward one end of said cylinder, whereby said rod portionmoves said reciprocative member of said gun, said gun actuating member being arranged whereby when near said end of said cylinder said member abuttingly engages said valve to thereby move said valve through its stroke and open said outlet port means, said gun actuating member being adapted to be returned to the opposite end of said cylinder by said reciprocative gun member following said movement, and being arranged to abuttingly engage, said valve when near said other end of said cylinder to thereby move said valve through itsst-roke in the opposite direction to close said outlet port mean and open said inlet port means.

References Citedin the file of this patent UNITED STATES PATENTS 

